Necrotic death of neurons is the critical outcome of stroke, ischemia, and traumatic injury, and contributes to many devastating neurodegenerative diseases. Studies in the model nematode Caenorhabditis elegans have characterized a cellular necrosis pathway that is distinct from apoptosis. Neuronal cell death via this pathway can be initiated by ion-channel hyperactivation or by other specific insults. Full execution of necrotic neuron death requires multiple gene products, suggesting the existence of multiple potentially druggable targets. A mammalian homolog of a C. elegans necrosis-inducing ion channel contributes to neuron death during ischemic acidosis, suggesting that mechanisms of necrotic cell death, like those of apoptosis, are conserved from nematodes to humans. Current therapeutic interventions for clinical conditions characterized by neuronal cell death are largely palliative and do little to promote neuron survival. The development of effective neuroprotective therapies has been hampered by an incomplete understanding of the underlying cell death mechanisms, and by a lack of pertinent disease models that are suitable for high- throughput screening. C. elegans necrosis provides a powerful genetically-validated, high-throughput disease model that circumvents these barriers. This project will employ the C. elegans whole-organism model of neural cell necrosis for microwell-format compound screening to identify novel neuroprotective drug candidates. Two specific aims will be pursued during this phase I SBIR: (1) Create a robust, validated, whole-organism screen for novel inhibitors of neuronal necrosis. Preliminary studies have produced protocols for automated, high-throughput analysis of neuron survival in animals arrayed in 96-well plates. These protocols will be used to develop a microwell- format assay for compounds that block necrotic cell death. (2) Execute a pilot screen of -3000 highly selected compounds to identify neuroprotective agents. A library of known bioactive compounds, including many currently marketed drugs, will be screened for compounds that block necrotic cell death due to ion channel hyperactivation. The screening strategy will further include appropriate counterscreens and secondary assays for protection against multiple distinct necrosis-inducing stimuli in order to identify neuroprotective compounds for further evaluation in mammalian models of ischemia in Phase II. The long-term goal of this project is the development of neuroprotective drugs to address unmet needs in injury and disease of the nervous system. The targeted cell death pathway contributes to neural damage in ischemic stroke, which is responsible for approximately 180,000 deaths annually in the U.S. The proposed screen opens up a novel therapeutic approach to this major public health problem. [unreadable] [unreadable]